The music of Muddy Waters is steeped in the blues tradition of the early twentieth century but also plays a key role in the development of the rock music of the 1960s and '70s. The importance of Waters's music can be understood more fully by exploring its engagement with blues music's harmonic and melodic characteristics. This article posits two approaches to blues tonal space: the networked and the laddered. The first is underpinned by the cyclical potential of equal temperament and is characterised by descending chromatic motions. The second is underpinned by the harmonic series and is characterised by the microtonal shaping of pitch content within the framework of a ladder that approximates an equal-tempered major-minor seventh chord.After explaining the details of these approaches with reference to an early blues recording by Alberta Hunter and Fats Waller, the article examines the ways in which Muddy Waters favours the laddered approach but develops novel ways of referencing the networked system, often combining or synergising aspects of each. This analysis yields insight into the potential for interchange in blues between networked and laddered tonal space. This interchange exploits (1) the structural importance of the major-minor seventh chord, (2) the special weight afforded the sonority of the minor third and (3) the affinity between microtonal and chromatic step motion in this genre.